body. These organs can be classified functionally nto two main groups. The primary lymphoid organs provide appropriate microenvironments for the development and maturation of lymphocytes. The secondary lymphoid organs rap antigen from defined tissues or vascular spaces and are sites where mature lymphocytes can interact effectively with that antigen. Blood vessels and lymphatic systems connect these organs, uniting them into a functional whole Carried within the blood and lymph and populating the Macrophage Interacting with
cell receptor when complexed with MHC,are called antigens. The molecular properties of antigens and he way in which these properties ultimately contribute to immune activation are central to our understanding of the mmune system. This chapter describes some of the molecu- Complementarity of Interacting Surfaces of Antibody(left) lar features of antigens recognized by B or T cells. The chap and Antigen(rig ter also explores the contribution made to immunogenicity by the biological system of the host; ultimately the biological system determines whether a molecule that combines with a a Immunogenicity Versus Antigenicity Bor T cells antigen-binding receptor can then induce an im
